| Nowadays, the “energy crisis” and “environmental pollution” continued to affect humans. Solar cells is an important means which can use solar energy efficiently and offers the potential for the future to solve the energy crisis and environmental pollution. Cu In1-x Gax Se2(CIGS) thin film solar cells is high conversion efficiency, low-cost and stable. Among the many methods of CIGS thin film preparation, electrodeposition has attracted significant interests to prepare CIGS thin film due to its low-cost, easy operation, simple equipment. Ionic liquid as a novel green solvents, having excellent characteristics such as wide electrochemical window, stable, non-toxic. To this end, this paper puts forward the conception of ionic liquid electrodeposition of CIGS thin film.This paper describes the preparation of CIGS solar cell absorption layer in "twostep" which means use electrodeposition preparation Cu-In/Ga metal prefabricated layer first and presents a program of preparation of CIG prefabricated metal layer, then the CIGS thin film is obtained by processing selenide. First of all research the electrochemical kinetics(discharge step, reversibility) nature of copper indium in [BMIM][Tf O]ionic liquid by electrochemical methods.Then,the paper focuses explore the impact of solution concentration, temperature and deposition potential to alloy deposited layer elements proportion, element distribution, morphology and crystal structure, worked out a basic law of co-deposited copper indium alloy. Based on these, Gallium was analyzed through circulation volt-ampere curve in [BMIM] [Tf O] cyclic voltammetric behavior in ionic liquids. Studied the gallium deposited law on copper indium thin film.Finally selected Cu Cl2(25 mmol/L) In Cl3(38 mmol/L), and the codeposition potential- 1.8V, deposition time 30 min, deposition temperature 60 ℃ Cu- In layer preparation technology conditions, Ga Cl3(200 mmol/L), the deposition potential-1.6V, sedimentary time 20 min, deposition temperature 50 ℃ Ga layer deposition process parameters. Such preparation of Cu- In/Ga metal prefabricated layer surface flat even,and the sediment composition is Cu1In0.796Ga0.439.In addition, this paper studied the selenide annealing process of Cu-In/Ga metal film forming technology of the precast floor on technology system. Explore "enclosed stone ink cartridge" way of selenizing, studied the annealing temperature and annealing time on the influence of the film-forming process. Analyzed phase composition, texture and residual stress of the CIGS thin film through testing means such as XRD, Raman spectra, TEM, characterized the surface morphology and composition of the CIGS thin film by SEM、EDS and some other analysis and testing methods. Characterized the optical properties CIGS thin film by UV-visible spectrophotometer and other testing methods. The results showed that ideal crystallization cannot occur when annealing temperature is below 450℃; when the selenide temperature over 500℃ in addition to chalcopyrite CIGS also easy to form the other phase; When the annealing time is too short, can not cause metal elements in the film fully recrystallization; and when the annealing time is too long will result in great loss of film of indium and gallium and generate rich copper CIGS and deviating from the expected elements ratio. The study found that annealing temperature of 450 ~500 ℃, 15 min annealing time is more appropriate annealing conditions.Alloying treatment of 360℃ in the annealing process plays an important role for the Reduce interlaminar stresses CIGS thin film materials, and promote the formation of crystalline phase, and enhance the integrity of the film structure. |
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